Biodegradable aliphatic-aromatic copolyesters, methods of manufacture, and articles thereof

ABSTRACT

Biodegradable compositions containing an aliphatic-aromatic copolyester derived from aromatic polyesters. Methods of making the compositions and articles made from the compositions.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 61/245,073, filed Sep. 23, 2009, the contents of which areincorporated by reference herein in their entirety.

BACKGROUND

This invention relates to biodegradable aliphatic-aromatic copolyesters,combinations thereof with other polymers, and methods of manufacture ofthe copolyesters and compositions. These polymers and combinationsthereof are useful as molded or extruded plastic objects, films, andfibers.

It is well known that billions of pounds of poly(ethylene terephthalate)(PET) are discarded into landfills annually all over the world. Some ofthe PET that is not reused is currently incinerated. The disposal of PETinto landfills or its incineration is harmful to the environment. If PET(scrap) material could be converted into a useful aliphatic-aromaticcopolyester, then there would exist a valuable environmentallyprogressive way to meet the unmet need to effectively use underutilizedscrap PET in aliphatic-aromatic copolyester compositions.

For the foregoing reasons, there remains a long felt, unmet need todevelop improved processes to effectively utilize polyester scrap.

There further remains a long felt, unmet need to need to develop newprocesses for making high molecular weight aliphatic-aromaticcopolyesters, having good color and other thermal and mechanicalproperties.

Further for the foregoing reasons, there remains a long unfelt need todevelop new articles from molding compositions that that have usefulperformance properties, particularly where the articles utilizealiphatic-aromatic copolyesters derived from polyester scrap.

SUMMARY

The invention relates to a biodegradable composition comprising acombination of:

(i) from more than 10 to 59.99 wt. %, based on the total weight of thecomposition, of an aliphatic aromatic copolyester having a numberaverage molecular weight of at least 20,000 Daltons and a polydispersityindex from 2 to less than 6, specifically 2 to 5, wherein thecopolyester comprises:

-   -   (a) a first dihydric alcohol group derived from a first dihydric        alcohol selected from the group consisting of ethylene glycol,        1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol,        2,3-butanediol, 1,4-butanediol, tetramethyl cyclobutanediol,        isosorbide, hexylene glycol, bio-derived diols, and a        combination thereof,    -   (b) an aromatic dicarboxylic acid group derived from a reaction        of        -   (bi) the first dihydric alcohol,        -   (bii) an aromatic polyester selected from the group            consisting of poly(ethylene terephthalate), poly(butylene            terephthalate), polytrimethylene terephthalate, and a            combination thereof, and        -   (biii) an aliphatic dicarboxylic acid having the general            formula (CH₂)_(m)(COOH)₂, where m is an integer from 2 to            10,    -   (c) an aliphatic dicarboxylic acid group,    -   (d) a second dihydric alcohol group derived from the polyester        and incorporated into the copolyester when the polyester reacts        with the first dihydric alcohol and the aliphatic dicarboxylic        acid, wherein the second dihydric alcohol group is the residue        of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol,        1,2-butanediol, 2,3-butanediol, 1,4-butanediol, tetramethyl        cyclobutanediol, isosorbide, a cyclohexanedimethanol, a hexylene        glycol, a bio-derived diol, and a combination thereof,    -   (e) the residue of from 0 to 0.10 wt. %, based on the        aliphatic-aromatic copolyester, of a phosphate compound, and    -   (f) the residue of from 0 to 1.50 wt. %, based on the        aliphatic-aromatic copolyester, of an addition copolymer        comprising the residue of a glycidyl monomer;

(ii) from more than 40 to less than 89.99 wt. %, based on the totalweight of the composition, of an aliphatic polyester, aliphaticpolycarbonate, starch, aromatic polyester, cycloaliphatic polyester,polyesteramide, or aromatic polycarbonate; and

(iii) from 0.01 to 5.00 wt. %, based on the total weight of thecomposition, of a nucleating agent, antioxidant, UV stabilizer,plasticizer, epoxy compound, melt strength additive, or a combinationthereof;

wherein the wt. % of (i), (ii), and (iii) totals 100 wt. %; and

wherein a bar having a thickness of 3.2 mm molded from the compositionhas a notched Izod impact strength of at least 920 J/m determined inaccordance with ASTM D256 at 23° C., and a flexural modulus of at least750 MPa determined in accordance with ASTM D790.

In another embodiment, the invention relates to a biodegradablecomposition comprising:

(i) from more than 93.4, e.g., more than 95 wt. %, based on the totalweight of the composition, of a copolyester having a number averagemolecular weight of at least 20,000 Daltons and a polydispersity indexfrom 2 to 6, specifically 2 to 5, wherein the copolyester comprises:

-   -   (a) a first dihydric alcohol group derived from a first dihydric        alcohol selected from the group consisting of ethylene glycol,        1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol,        2,3-butanediol, 1,4-butanediol, tetramethyl cyclobutanediol,        isosorbide, hexylene glycols, bio-derived diols and a        combination thereof,    -   (b) an aromatic dicarboxylic acid group derived from a reaction        of        -   (bi) a first dihydric alcohol,        -   (bii) an aromatic polyester selected from the group            consisting of poly(ethylene terephthalate), poly(butylene            terephthalate), polytrimethylene terephthalate, and a            combination thereof, and        -   (biii) an aliphatic dicarboxylic acid having the general            formula (CH₂)_(m)(COOH)₂, wherein m is an integer from 2 to            10,    -   (c) an aliphatic dicarboxylic acid group derived from the        aliphatic dicarboxylic acid, and    -   (d) a second dihydric alcohol group derived from the polyester        and incorporated into the copolyester when the polyester reacts        with the first dihydric alcohol and the aliphatic dicarboxylic        acid, wherein the second dihydric alcohol group is the residue        of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol,        1,2-butanediol, 2,3-butanediol, 1,4-butanediol, tetramethyl        cyclobutanediol, isosorbide, a cyclohexanedimethanol, a hexylene        glycol, a bio-derived diol, and a combination thereof,    -   (e) the residue of from 0 to 0.10 wt. %, based on the        aliphatic-aromatic copolyester, of a compound containing a        phosphate group, and    -   (f) the residue of from 0 to 1.50 wt. %, based on the        aliphatic-aromatic copolyester, of an addition copolymer        comprising the residue of a glycidyl monomer; and

(ii) from 0 to 5 wt. % of a nucleating agent, an antioxidant, orcombination thereof, wherein the wt. % of components (i) and (ii) totals100 wt %.

In another embodiment, a process for making a biodegradable copolyestercomprises:

a) reacting

-   -   (1) an aromatic polyester with    -   (2) a first dihydric alcohol selected from the group consisting        of ethylene glycol, propylene glycol, butylene glycol,        1,4-butanediol tetramethyl cyclobutanediol, isosorbide,        cyclohexanedimethanol, bio-derived alcohols, and hexylene        glycol, and    -   (3) an aliphatic dicarboxylic acid of the formula        (CH₂)_(m)(COOH)₂, wherein m is 4 to 10,        at a temperature from 160° C. to less than 250° C. in the        presence of a transition metal catalyst, e.g., a titanium        alkoxide catalyst to form a first mixture;

b) subjecting the first mixture to vacuum distillation at a pressure ofless than 2 Torr and a temperature of 220 to less than 260° C., to forma molten copolyester; and

c) optionally reacting the molten copolyester with from 0 to 1.50 wt. %of a phosphate compound, from 0 to 1.50 wt. % of an addition copolymercomprising the residue of a glycidyl monomer, or a combination thereof,for at least 5 minutes, to form the copolyester.

In another embodiment, the invention relates to a process for making thebiodegradable composition, the process comprising

a) reacting

-   -   (1) an aromatic polyester with    -   (2) a first dihydric alcohol selected from the group consisting        of ethylene glycol, propylene glycol, butylene glycol,        1,4-butanediol tetramethyl cyclobutanediol, isosorbide,        cyclohexanedimethanol, bio-derived diols, and hexylene glycol,        and    -   (3) an aliphatic dicarboxylic acid of the formula        (CH₂)_(m)(COOH)₂, wherein m is 4 to 10,        at a temperature from 160° C. to less than 250° C. in the        presence of a transition metal catalyst to form a first mixture;

b) subjecting the first mixture to vacuum distillation at a pressure ofless than 2 Torr and a temperature of 220 to less than 260° C., to forma molten copolyester; and

c) optionally reacting the molten copolyester with from 0 to 1.50 wt. %of a phosphate compound, from 0 to 1.50 wt. % of an addition copolymercomprising the residue of a glycidyl monomer, or a combination thereof,for at least 5 minutes, to form the copolyester; and

(d) adding to the aliphatic-aromatic copolyester:

-   -   (i) from more than 40 to 89.99 wt. %, based on the total weight        of the composition, of a polymer selected from the group        consisting of an aliphatic polyester, aliphatic polycarbonate,        starch, aromatic polyester, cycloaliphatic polyester,        polyesteramide, aromatic polycarbonate, and a combination        thereof; and    -   (ii) from 0.01 to 5.00 wt. % of an additive selected from the        group consisting of a nucleating agent, antioxidant, UV        stabilizer, plasticizer, epoxy compound, melt strength additive,        and a combination thereof, to form the biodegradable        composition;    -   wherein the total wt. % of the copolymer, the polymer, and the        additive is 100 wt. %.

The invention also relates to articles made from the compositionsdescribed above, e.g., films or sheets.

DESCRIPTION OF THE FIGURE

The FIGURE shows apparent melt viscosity property changes of materialsdiscussed in the Examples.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims.

DETAILED DESCRIPTION

This invention is based on the discovery that it is possible make abiodegradable composition in situ from used polyesters, where thecomposition is suitable for film packaging applications. Advantageously,the utilization of used polyesters allows a polyester that wouldotherwise be discarded as waste to be used productively. In oneembodiment, the biodegradable composition can also be made withrenewable materials such as adipic acid, sebacic acid, and bio-glycolssuch as bio-1,3-propane diol. By using a specific combination ofstabilizers, we have also discovered that we can also make a compositionwith a copolyester having a white color, which is extremely useful forfilm packaging applications.

Our biodegradable composition includes various versions. In one version,our composition includes a combination of an aliphatic-aromaticcopolyester, a second polymer, and an additive. Our composition can alsoinclude the combination of the aliphatic-aromatic copolyester.

The term “white,” as used in this application, means that the materialbeing described as white exhibits an L* value that is at least 75, or atleast 80, or at least 85 with a corresponding set of “a” and “b” valuesthat are substantially close to 0, (less than 5 units on the CIE colorscale), where the “a” represents red and green hues and “b” representsblue and yellow hues of the white material on the CIE LAB color scale.The L* value can range from 75, or 80, or 85 to 100. The “L*, a, b”method for describing colors is will known and developed by the CIE(Commission Internationale de l'Eclairage). The CIE providesrecommendations for colorimetry by specifying the illuminants, theobserver and the methodology used to derive values for describing color3 coordinates are utilized to locate a color in a color space which isrepresented by L*, a* and b*. When a color is expressed in CIELAB, L*defines lightness, if a value is closer to 0 it means total absorptionor how dark a color is. If the L* value is closer to 100 it means totalreflection or how light a color is. a* denotes how green or red a coloris, whereas b* represents how blue or yellow a color is.

The term “recycle” as used herein refers to any component that has beenmanufactured and either used or intended for scrap. Thus, a recyclepolyester can be polyester that has been used, for example in drinkingbottle, or that is a byproduct of a manufacturing process, for examplethat does not meet a required specification and therefore wouldotherwise be discarded or scrapped. Recycle materials can thereforecontain virgin materials that have not been utilized.

The prefix “bio-” or “bio-derived” as used herein means that thecompound or composition is ultimately derived from a biological source,e.g., “bio-1,3-propane diol” is derived from a biological (e.g., plantor microbial source) rather than a petroleum source. Similarly, theprefix “petroleum-” or “petroleum-derived” means that the compound orcomposition is ultimately derived from a petroleum source, e.g., a“petroleum-derived poly(ethylene terephthalate) is derived fromreactants that are themselves derived from petroleum.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. Further unless definedotherwise, technical, and scientific terms used herein have the samemeaning as is commonly understood by one of skill in the art to whichthis invention belongs. Compounds are described using standardnomenclature. For example, any position not substituted by any indicatedgroup is understood to have its valency filled by a bond as indicated,or a hydrogen atom. A dash (“—”) that is not between two letters orsymbols is used to indicate a point of attachment for a substituent. Forexample, —CHO is attached through carbon of the carbonyl group.

Other than in operating examples or where otherwise indicated, allnumbers or expressions referring to quantities of ingredients, reactionconditions, and the like, used in the specification and claims are to beunderstood as modified in all instances by the term “about.” Variousnumerical is present in an amount from are disclosed in this patentapplication. Because these is present in an amount from are continuous,they include every value between the minimum and maximum values. Unlessexpressly indicated otherwise, the various numerical is present in anamount from specified in this application are approximations. Theendpoints of all ranges directed to the same component or property areinclusive and independently combinable.

All ASTM tests and data are from the 2003 edition of the Annual Book ofASTM Standards unless otherwise indicated.

The compositions include a biodegradable aliphatic-aromatic copolyesterthat is derived in situ from the reaction of a dihydroxy compound and analiphatic dicarboxylic ace with an aromatic polyester, in particular arecycle poly(ethylene terephthalate). Accordingly, the copolyestercontains (a) a first dihydric alcohol group; (b) an aromaticdicarboxylic acid, (c) an aliphatic dicarboxylic acid group; and (d) asecond dihydric alcohol group. In one embodiment, a residue of acompound containing a phosphate group (e) is present, the residue of anaddition copolymer based on a glycidyl monomer, that is, an additionpolymer comprising the residue of a glycidyl monomer (f) is present, ora combination thereof.

The first dihydric alcohol group incorporated into the copolyester canbe derived from any first dihydric alcohol that reacts with thealiphatic dicarboxylic acid and the aromatic polyester to form the firstdihydric alcohol group in the copolyester. Examples of suitable dihydricalcohols can include ethylene glycol, 1,2-propylene glycol,1,3-propylene glycol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol,tetramethyl cyclobutanediol, isosorbide, cyclohexane dimethanol(including 1,2-, 1,3-, and 1,4-cyclohexane dimethanol), bio-deriveddiols, hexylene glycols, and a combination thereof. Any of the foregoingdihydric alcohols can be derived from a biological source. In oneembodiment all or a portion of the dihydric alcohols are derived from abiological source. “Bio-derived diols” as used herein refers alcoholsother than those named and derived from a biological source, e.g.,various pentoses, hexoses, and the like. The first dihydric alcohol isgenerally added to a mixture containing the aromatic polyester and thealiphatic dicarboxylic acid.

The aromatic dicarboxylic acid group is incorporated into thecopolyester forms when the polyester reacts with the first dihydricalcohol and the aliphatic dicarboxylic acid under conditions sufficientto form the copolyester. Examples of the aromatic dicarboxylic acidgroup include isophthalic acid groups, terephthalic acid groups, and acombination thereof. The aromatic polyester is thus a polyestercontaining aromatic dicarboxylic acid residues, and can be any aromaticpolyester, which when reacted with the first dihydric alcohol and analiphatic dicarboxylic acid, forms a copolyester containing aromaticdicarboxylic acid groups, first dihydric alcohol groups, and seconddihydric alcohol groups. In one embodiment, the aromatic polyestercontains (i) at least 40 mole % of total acid groups as aromaticdicarboxylic acid groups and (ii) is selected from the group consistingof poly(ethylene terephthalate), poly(butylene terephthalate),polypropylene terephthalate, copolymers of the foregoing, andcombinations thereof. Specific examples of suitable aromatic polyestersinclude poly(ethylene terephthalate), poly(butylene terephthalate),polytrimethylene terephthalate, and combinations thereof. The aromaticpolyester can be petroleum-derived or bio-derived, and in one embodimentis a recycle aromatic polyester, for example recycle poly(ethyleneterephthalate). The recycle polyester can be in any form, e.g., flakes,pellets, and the like.

The aliphatic dicarboxylic acid group is incorporated into thecopolyester when the aromatic polyester reacts with the first dihydricalcohol and the aliphatic dicarboxylic acid to form the copolyester.Examples of the aliphatic dicarboxylic acid include components havingthe general formula (CH₂)_(m)(COOH)₂, where m is an integer from 2 to10. The aliphatic dicarboxylic acid can be decanedioic acid, adipicacid, or sebacic acid. When the aliphatic dicarboxylic acid is adipicacid, the value of m is 4. When the aliphatic dicarboxylic acid issebacic acid, the value m is 8. In one embodiment all or a portion ofthe aliphatic dicarboxylic acid is a bio-derived aliphatic dicarboxylicacid.

The aliphatic-aromatic copolyester further comprises a second dihydricalcohol group that is derived from the aromatic polyester, and that isincorporated into the copolyester when the first dihydric alcohol reactswith the aromatic polyester in the presence of the aliphaticdicarboxylic acid. As such, unlike the first dihydric alcohol, thesecond dihydric alcohol is not added to a mixture containing thepolyester and the aliphatic dicarboxylic acid. Examples of suitablesecond dihydric alcohol groups can include the residues of ethyleneglycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol,2,3-butanediol, 1,4-butanediol, tetramethyl cyclobutanediol, isosorbide,cyclohexane dimethanol (including 1,2-, 1,3-, and 1,4-cyclohexanedimethanol), hexylene glycol, and a combination thereof. Because thesecond dihydric alcohol groups are derived from the aromatic polyester,the first and the second dihydric alcohol groups can be the same ordifferent. For example, the first dihydric alcohol groups can beresidues of 1,4-butanediol, 1,3-propanediol, ethylene glycol, orcombinations thereof and the second dihydric alcohol groups can beethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, orcombinations thereof. The first dihydric alcohol groups and the seconddihydric alcohol groups are the same in one embodiment. The firstdihydric alcohol groups and the second dihydric alcohol groups aredifferent in another embodiment.

In a specific embodiment, the first dihydric alcohol is 1,4-butanediol,1,3-propanediol, ethylene glycol, or a combination thereof the aliphaticdicarboxylic acid is decanedioic acid, adipic acid, sebacic acid, or acombination thereof, the second dihydric alcohol group is the residue ofethylene glycol, 1,3-propanediol, 1,4-butanediol, or a combinationthereof, and the aromatic polyester is a poly(trimethyleneterephthalate) derived from petroleum-derived 1,3-propanediol,poly(trimethylene terephthalate) derived from bio-derived1,3-propanediol, poly(butylene terephthalate) derived frompetroleum-derived 1,4-butanediol, poly(butylene terephthalate) derivedfrom bio-derived 1,4-butanediol, poly(trimethylene terephthalate)derived from post-consumer poly(ethylene terephthalate), poly(butyleneterephthalate) derived from post-consumer poly(ethylene terephthalate),virgin poly(ethylene terephthalate), recycled poly(ethyleneterephthalate), post-consumer poly(ethylene terephthalate), recycledpoly(trimethylene terephthalate), recycled copolyesters of terephthalicacid with ethylene glycol and cyclohexane dimethanol, and combinationsthereof.

The amount the first dihydric alcohol group and the second dihydricalcohol group in the copolyester can vary. In one embodiment, the firstdihydric alcohol group is present in an amount from 80 to 99.6 mole % oftotal dihydric alcohol content and the second dihydric alcohol group ispresent in an amount from 0.4 mole % to 20.0 mole % of the totaldihydric alcohol content. In another embodiment, the first dihydricalcohol group is present in an amount from 85 to 99.4 mole % of totalcontent of dihydric alcohol groups in the composition and the seconddihydric alcohol group is present in an amount from 0.6 to 15.0 mole %of the total dihydric alcohol content.

The relative amounts of the aromatic dicarboxylic acid group and thealiphatic dicarboxylic acid group can vary. In one embodiment, thearomatic dicarboxylic group and the aliphatic dicarboxylic group have anaromatic dicarboxylic group:aliphatic dicarboxylic group mole ratio from0.6:1 to 6:1. In another embodiment, the aromatic dicarboxylic group andthe aliphatic dicarboxylic group are present at an aromatic dicarboxylicgroup:aliphatic dicarboxylic group mole ratio from 0.6:1 to 1.3:1.

The content of aromatic acid groups (in particular isophthalic acidgroups and terephthalic acid groups) in the copolyester will varydepending on the aromatic polyester used and the reaction conditions. Inone embodiment the aromatic dicarboxylic acid group contains from 0.2 to3.0 mole % of isophthalic acid group and from 47 to 49.8 mole % percentof terephthalic acid groups, based on the total moles of acid groupspresent in the copolymer.

In a specific embodiment, the first dihydric alcohol group is present inan amount from 80 to 99.6 mole % of the total dihydric alcohol contentand the second dihydric alcohol group is present in an amount from 0.4mole % to 20.0 mole % of the total dihydric alcohol content, thearomatic dicarboxylic group and the aliphatic dicarboxylic group have anaromatic dicarboxylic group:aliphatic dicarboxylic mole ratio from 0.6:1to 6:1, and the aromatic dicarboxylic acid group contains from 0.2 to3.0 mole % of isophthalic acid groups and from 47 to 49.8 mole %terephthalic acid groups, each based on the total moles of dicarboxylicacid groups in the copolymer.

The copolyesters can further comprise other residues present in thearomatic polyester, including catalyst residues from the manufacture ofthe aromatic polyester, residues from additives in the aromaticpolyester, or residues arising from side reactions that occur duringmanufacture of the aromatic polyester and/or the reaction of the firstdihydric alcohol, the aliphatic diacid, and the aromatic polyester.

For example, when the aromatic polyester includes a poly(ethyleneterephthalate) component, the aromatic polyester can include apoly(ethylene terephthalate) homopolymer, a poly(ethylene terephthalate)copolymer, or a combination thereof, and the aliphatic-aromaticcopolyester contains a residue derived from the poly(ethyleneterephthalate) composition. Residues derived from the poly(ethyleneterephthalate) component can be ethylene glycol groups, diethyleneglycol groups, isophthalic acid groups, antimony-containing compounds,germanium-containing compounds, titanium-containing compounds,cobalt-containing compounds, tin-containing compounds, aluminum,aluminum salts, 1,3-cyclohexanedimethanol isomers,1,4-cyclohexanedimethanol isomers, alkaline salts, alkaline earth metalsalts, phosphorous-containing compounds and anions, sulfur-containingcompounds and anions, naphthalene dicarboxylic acids, 1,3-propanediolgroups, or combinations thereof. In one embodiment, the residue derivedfrom the poly(ethylene terephthalate) component comprises ethyleneglycol groups, diethylene glycol groups, and more particularly acombination of ethylene glycol groups, diethylene glycol groups.

Accordingly, our invention includes embodiments in which the residuederived from the poly(ethylene terephthalate) component includesindividual elements and combinations of the foregoing materials. Theresidue derived from the poly(ethylene terephthalate) component, forinstance, can comprise isophthalic acid groups. In an embodiment, theresidue derived from the poly(ethylene terephthalate) component furthercomprises the cis isomer of 1,3-cyclohexanedimethanol, cis isomer of1,4-cyclohexanedimethanol, trans isomer of 1,3-cyclohexanedimethanol,trans isomer of 1,4-cyclohexanedimethanol and combinations thereof. Inone embodiment, the residue derived from the poly(ethyleneterephthalate) component includes a combination of ethylene glycol anddiethylene glycol groups, optionally with isophthalic acid groups, andcan further comprise the cis isomer of 1,3-cyclohexanedimethanol, thecis isomer of 1,4-cyclohexanedimethanol, the trans isomer of1,3-cyclohexanedimethanol, trans isomer of 1,4-cyclohexanedimethanol, orcombinations thereof. In an embodiment, the residue derived from thepolyethylene terephthalate component comprises ethylene glycol groups,diethylene glycol groups, isophthalic acid groups, the cis isomer ofcyclohexanedimethanol, the trans isomer of cyclohexanedimethanol, andcombinations thereof. In an embodiment, the residue derived from thepoly(ethylene terephthalate) component comprises ethylene glycol groups,diethylene glycol groups, and cobalt-containing compounds; in anotherembodiment the a residue derived from the poly(ethylene terephthalate)component further comprises isophthalic acid groups.

When the aromatic polyester is poly(butylene terephthalate), thecomposition can contain poly(butylene terephthalate) residues such asbutane diol, titanium, tin, or combinations thereof, optionally togetherwith epoxies.

When the aromatic polyester is poly(trimethylene terephthalate), thecomposition contains poly(trimethylene terephthalate) residues such aspropane diol, titanium, tin, or combinations thereof.

The copolyester generally has a number average molecular weight of atleast 20,000 Daltons and a polydispersity index from 2 to less than 6,specifically 2 to 5. In one embodiment, the copolyester has a glasstransition temperature (Tg) from −35° C. to 0° C. In another embodiment,the copolyester has a melting temperature (Tm) from 90° C. to 160° C.

The copolyester can be made by any suitable method using the aromaticpolyester, the first dihydric alcohol, and the aliphatic diacid. In oneembodiment, the copolyester is manufactured by reacting the aromaticpolyester with the first dihydric alcohol and the aliphatic dicarboxylicacid at a temperature at an elevated temperature in the presence of atransition metal catalyst, to form a first mixture, and subjecting thefirst to a reduced pressure and an elevated temperature to form thecopolyester.

The copolyester can also be made with additional materials that can bepresent during any of the manufacturing steps, or added after formationof the molten copolyester, or after cooling of the molten copolyester.

For example, in an optional embodiment, the molten copolyester isfurther reacted with a phosphate compound for an effective time, forexample at least 5 minutes, specifically from 5 minutes to two hours. Inthis embodiment, the aliphatic-aromatic copolyester further comprises aresidue of the phosphate compound, either associated with the copolymeror covalently bound to the copolymer. Examples of the compoundcontaining a phosphate group include inorganic phosphate-containingcompounds such as phosphoric acid, zinc phosphate, and the like. Thephosphate compound can be present in an amount from 0 to 0.10 wt. % ofthe molten copolyester. Reacting can be at a temperature of, forexample, less than or equal to 250° C.

In another optional embodiment, the molten copolyester is furtherreacted with an addition copolymer comprising the residue of a glycidylester monomer for an effective time, for example at least 5 minutes,specifically from 5 minutes to two hours. In this embodiment, thealiphatic-aromatic copolyester further comprises a residue of theaddition copolymer, either associated with the copolymer or covalentlybound to the copolymer. Examples of the an addition copolymer based on aglycidyl monomer include an addition copolymer comprising the residue ofglycidyl acrylate, glycidyl methacrylate, or a combination thereof andthe residue of methyl methacrylate, methyl acrylate, styrene,alpha-methyl styrene, butyl methacrylate butyl acrylate, or combinationsthereof, for example styrene and methyl methacrylate. The additioncopolymer can be present in an amount from 0 to 1.50 wt. % of the moltencopolyester. Reacting can be at a temperature of, for example, less thanor equal to 250° C.

In a specific embodiment, the molten copolyester is further reacted withthe phosphate compound and the addition polymer, thereby providing thecopolymer with a residue of the phosphate compound and a residue of theaddition copolymer. Thus, the copolyester is manufactured by: a)reacting an aromatic polyester with a first dihydric alcohol and analiphatic dicarboxylic acid at a temperature from 160° C. to less than250° C. in the presence of a titanium alkoxide catalyst, to form a firstmixture, wherein the dihydric alcohol is ethylene glycol, propyleneglycol, butylene glycol, 1,4-butanediol tetramethyl cyclobutanediol,isosorbide, cyclohexanedimethanol, a bio-derived diol, or hexyleneglycol and wherein the aliphatic dicarboxylic acid is of the generalformula (CH₂)m(COOH)₂, wherein m=4 to 10; (b) subjecting the firstmixture to a pressure of less than 2 Torr, e.g., by vacuum distillation,and a temperature of 220 to less than 260° C. to form the copolyester;and (c) reacting the molten copolyester with a phosphate compound and anaddition copolymer based on a glycidyl compound for at least 5 minutes,and thereby forming the copolyester. Reacting can be at a temperatureof, for example, less than or equal to 250° C.

The biodegradable composition of the invention includes, in addition tothe copolyester, other components combined with the copolyester, forexample other polymers and additives, for example additives used in theformulation of molding compositions. Examples of the polymers includealiphatic polyesters, aromatic polycarbonates, aliphatic polycarbonates,starches, aromatic polyesters, aromatic polyesters, cycloaliphaticpolyesters, polyesteramides, and the like. The polymers can be wholly orpartially bio-derived, including petroleum-derived aromatic polyestersand bio-derived aromatic polyesters.

In a specific embodiment the copolyester is combined with an aliphaticpolyester, for example poly(lactic acid), polyhydroxyalkanoate,poly(butylene succinate), poly(butylene adipate), poly(butylenesuccinate adipate) and poly(caprolactone), or a combination thereof.Polyhydroxyalkanoates (PHAs) are linear polyesters produced in nature bybacterial fermentation of sugar or lipids, and include, for example,poly(R-3-hydroxybutyrate) (PHB or poly(3HB)).

In another specific embodiment the copolyester is combined with anaromatic polyester, for example a poly(trimethylene terephthalate)derived from petroleum-derived 1,3-propanediol, poly(trimethyleneterephthalate) derived from bio-derived 1,3-propanediol, poly(butyleneterephthalate) derived from petroleum-derived 1,4-butanediol,poly(butylene terephthalate) derived from bio-derived 1,4-butanediol,poly(trimethylene terephthalate) derived from post-consumerpoly(ethylene terephthalate), poly(butylene terephthalate) derived frompost-consumer poly(ethylene terephthalate), virgin poly(ethyleneterephthalate), recycled poly(ethylene terephthalate), post-consumerpoly(ethylene terephthalate), recycled poly(trimethylene terephthalate),recycled copolyesters of terephthalic acid with ethylene glycol andcyclohexane dimethanol, or a combination thereof.

The amounts of the copolyesters and the additives, for example a polymercan vary depending on the desired properties of the biodegradablecomposition. In an embodiment the additives are present in an amountfrom 2 to 90 wt. %, for example from 2 to 40 wt. % or from 40 to 90 wt.%, based on the total weight of the composition. When the copolyester isused with starch, the amount of starch can range from 40 to 90 wt. %,and the amount of polyester can range from 10 to 60%, based on the totalweight of the total composition. When the copolyester is used inconjunction with polylactic acid, the amount of the copolyester canrange from 40 to 90 wt % and the amount of polylactic acid can rangefrom 10 to 60 wt. %, specifically 40 to 60%, based on the total weightof the composition.

Additives ordinarily incorporated into polymer compositions can be used,with the proviso that the additives are selected so as to notsignificantly adversely affect the desired properties of thecomposition, for example, biodegradability, impact, flexural strength,color, and the like. Such additives can be mixed at a suitable timeduring the mixing of the components for forming the composition.Possible additives include impact modifiers, fillers, reinforcingagents, anti-oxidants, heat stabilizers, light stabilizers, ultravioletlight (UV) absorbers, plasticizers, lubricants, mold release agents,antistatic agents, colorants, blowing agents, flame retardants,anti-drip agents, and radiation stabilizers. Combinations of additivescan be used, for example an antioxidant, a UV absorber, and a moldrelease agent. The total amount of additives (other than any impactmodifier, filler, or reinforcing agents) is generally 0.01 to 5 wt. %,based on the total weight of the composition. In a specific embodiment,from 0.01 to 5.00 wt. % of a nucleating agent, antioxidant, UVstabilizer, plasticizers, epoxy compound, melt strength additive, or acombination thereof is used.

In one embodiment, the composition has a Notched impact strength as perASTM D256 method of at least 920 J/m and a flexural modulus as per ASTMD790 of at least 750 MPa.

Advantageously, the copolyester and compositions containing thecopolyester can be biodegradable. This means that the copolyester andcompositions containing the copolyester exhibit aerobicbiodegradability, as determined by ISO 14855-1:2005. ISO 14855-1:2005,as is known, specifies a method for the determination of the ultimateaerobic biodegradability of plastics, based on organic compounds, undercontrolled composting conditions by measurement of the amount of carbondioxide evolved and the degree of disintegration of the plastic at theend of the test. This method is designed to simulate typical aerobiccomposting conditions for the organic fraction of solid mixed municipalwaste. The test material is exposed to an inoculum, which is derivedfrom compost. The composting takes place in an environment whereintemperature, aeration and humidity are closely monitored and controlled.The test method is designed to yield the percentage conversion of thecarbon in the test material to evolved carbon dioxide as well as therate of conversion. Also specified is a variant of the method, using amineral bed (vermiculite) inoculated with thermophilic microorganismsobtained from compost with a specific activation phase, instead ofmature compost. This variant is designed to yield the percentage ofcarbon in the test substance converted to carbon dioxide and the rate ofconversion. Generally, our copolyesters (and compositions containingcopolyesters) exhibit a biodegradation (measured in % of solid carbon ofthe test item that is converted into gaseous, mineral C in the form ofCO₂), which is at least 30% after 75 days. In one embodiment, thecopolyesters (and compositions containing copolyesters) exhibit abiodegradation, which is at least 40% or 50% after 75 days. Thebiodegradation of the copolyesters (and compositions containingcopolyesters) can range from at least 30% to 50%, or at least 30% to60%, or at least 30% to 70%.

Advantageously, useful articles can be made from the copolyester andcompositions containing the copolyester. In a specific embodiment, anarticle is extruded, calendared, or molded, for example blow molded orinjection molded from the copolymer or the composition containing thecopolymer. The article can be a film or a sheet. When the article is afilm, the article can be formed by extrusion molding or calendaring thecopolyester or composition containing the copolyester. The copolyestersand compositions containing the copolyesters are useful for films, forexample film packaging applications, among other applications.

The typical film of the copolyester or copolyester composition has amodulus of elasticity as per ISO 527 method of at least 520 N/mm², atensile strength as per ISO 527 of at least 27 N/mm², and a tearstrength as per DIN 53373 of at least 38 J/mm.

As stated above, various combinations of the foregoing embodiments canbe used.

The invention is further described in the following illustrativeexamples in which all parts and percentages are by weight unlessotherwise indicated.

EXAMPLES

Following is a list of materials, acronyms, and selected sources used inthe examples.

PET: Poly(ethylene terephthalate)

BDO: 1,4-Butanediol (from BASF, with a purity specification of 99.5 wt.%)

PDO: 1,3-Propanediol (from various commercial sources)

SBA: Sebacic Acid (from INVISTA)

ADA: Adipic Acid (from INVISTA)

TPT: Tetraisopropyl titanate (from DuPont, commercial Tyzor grade)

TOT: Tetraorthobutenyl titanate (from Sigma-Aldrich)

PBT-co-sebacate: Poly(butylene terephthalate)-co-sebacate

PBT-co-adipate: Poly(butylene terephthalate)-co-adipate

PPT-co-sebacate: Poly(propylene terephthalate)-co-sebacate

CESA: Styrene-acrylate-epoxy oligomer

MZP: Zinc-bis-dihydrogen phosphate

TNPP: Trisnonylphenyl phosphate

SDP: Monosodium phosphate

SAPP: Sodium acid pyrophosphate

PLA: Poly(lactic acid)

HP: Phosphoric acid

IR 1330: IRGANOX 1330

IR 1010: IRGANOX 1010

TIDP: Triisododecylphospite

TPP Triphenylphosphite

Recycle PET in the form of flakes or pellets was obtained from acommercial vendor headquartered in India.

Examples 1-3

The purpose of Examples 1-3 was to prepare the copolyesterPBT-co-sebacate derived from PET in accordance with the invention. Theoverall quantity of individual materials and the reaction scale used inthe laboratory and pilot scale for Examples 1-3 are shown in Table 1.

TABLE 1 Amount of raw materials, reaction scale and reaction conditionsfor Examples 1-3. Scale of Catalyst EI¹ EI¹ Poly² Poly² Ex. ReactionPET:BDO SBA:BDO Ti Temp. Time Temp. Time No. (g) (mol/mol) (mol/mol)(ppm) (° C.) (min) (° C.) (min) 1 143.2 0.53 0.23 100 220 44 250 40 2143.2 0.38 0.38 100 220 46 250 33 3 33180 0.39 0.39 100 225 50 250 180¹EI = Ester interchange; ²Poly = Polymerization.

Techniques and Procedures Examples 1-3 Example 1

In Example 1, PBT-co-sebacate derived from PET was prepared in a labreactor from recycle PET flakes. Thus, 48 g (0.25 mol) of PET flakes,50.6 g (0.25 mol) of sebacic acid (SBA) and 58 g (0.65 mol) of1,4-butanediol (BDO) were introduced into a three neck round bottomflask. The reactor was placed in an oil bath the temperature of whichwas adjusted to 170° C. Next, 100 ppm of tetraisopropyl titanate (TPT)was added to the reaction mixture and the ester interchange (EI)temperature was increased to 220° C. with a rate of 2° C./min whilestirring at 260 rpm under nitrogen. The ester interchange step wascompleted in 46 minutes. The temperature of the reaction mixture wasincreased to 250° C. The residual PET flakes was completely melted in 10minutes. The polymerization stage was conducted at the same temperaturewith the vacuum adjusted to less than 1 Torr for 33 minutes.

Example 2

In Example 2, PBT-co-sebacate derived from PET was prepared on a labscale with the same raw materials in a mole ratio of 0.35:0.15:0.65 (PETflakes:SBA:BDO). The process steps and conditions were otherwiseidentical to those of Example 1.

Example 3

Example 3 shows the pilot plant scale-up of the manufacture ofPBT-co-sebacate polymer derived from PET. The helicone reactor had acapacity of 200 liters and was equipped with a special design of twinopposing helical blades with a 270 degree twist; constructed of 316stainless steel with 16 g polish finish. The blade speed could be variedfrom 1 to 65 rpm. The agitators were connected to a Constant TorqueInverter Duty Motor, which operated at 230/460 VAC, 3 PH, and 60 Hz.These agitators provided excellent surface area for the polymer melt inorder to build molecular weight. The helicone was also designed with anoverhead condenser to condense the vapors in the glycolysis,transesterification (if any) and polymerization stages.

PET flakes (10.18 kg, 52.74 mol), BDO (12.29 kg, 136.4 mol), SBA (10.70kg, 52.74 mol), and TPT (10.7 ml) were charged to the helicon reactor at175° C. under nitrogen atmosphere. The agitator speed was set at 67% ofmaximum. Heating continued to 225° C. The butanediol was refluxed intothe reactor for 2 hours. The design of the overhead condenser system didnot allow a complete reflux of the butanediol.

For the polymerization stage (also referred to as ‘poly stage’), thetemperature of the heating oil (for the helicone) was set to 250° C.Then a vacuum was applied to the helicone reactor and the reflux ofbutanediol to the reactor was discontinued. The speed of the agitatorwas set to 60% of max and the target amps of the motor were 3.5 amps.The system pressure was brought down to 1.2 mm Hg by the vacuum blower.During polymerization or polycondensation stage, excess BDO, andresidual ethylene glycol (EG) were removed, along with tetrahydrofuran(THF) and water. The reaction was carried out until the polymer massreached its end of 2^(nd) build. The reaction was stopped and thepolymer was cast in blobs. The products were then allowed to dry andground into pellets.

Results Examples 1-3

Results for Examples 1-3 are shown in Tables 2 and 3. Table 2 shows theglass transition temperature (T_(g)), melting temperature (T_(m))obtained from differential scanning calorimetry (DSC), molecular weightdata obtained from gel permeation chromatography (GPC), and intrinsicviscosity (I. V.) for the Examples 1, 2, and 3. Table 2 also shows meltvolume rate (MVR) and melt flow rate (MFR) for the Example 3. MVR andMFR on pellets (dried for 2 hours at 80° C. prior to measurement) weremeasured according to ISO 1133 at 190° C. and 2.16 kg. Table 3 shows thecomposition of the polymers as determined by ¹H NMR analysis. Acapillary rheometer was used to determine an apparent melt viscosityaccording to ISO 11443 when a sample was sheared at a wide range ofshear rate at a temperature of 170 and 190° C. A 1 mm inside-diametricand 20 mm long orifice was used for measurement.

TABLE 2 Thermal, molecular weight, and I.V. analysis results. MVR MFREx. Tg Tm (mL · 10 (mL · 10 No. (° C.) (° C.) Mn Mw PDI I.V. min⁻¹)min⁻¹) 1 −14 150 27000 129000 4.7 1.044 NA NA 2 −27 103 29500 138000 4.71.257 NA NA 3 −32 103 34000 135000 4.0 1.255 8.01 8.19

TABLE 3 Composition analysis results for PBT- co-sebacate resin derivedfrom PET. Isophthalic Terephthalic Sebacic BDO EG Ex. Groups GroupsGroups Groups Groups No. Mole % Mole % Mole % Mole % Mole % 1 0.8 35.714.4 45.5 3.6 2 0.7 26.1 23.9 48.0 1.3 3 0.6 26.4 24.1 46.9 2.1

Discussion Examples 1-3

The results indicate that the aliphatic-aromatic copolyesterPBT-co-sebacate derived from PET in accordance with the invention wassuccessfully prepared. The results show that the process that was usedto make the copolyester enabled the copolyester to obtain a highmolecular weight. The results also show that residues of thepoly(ethylene terephthalate) that was used to make the copolyester wereincorporated into the copolyester. Also, Example 3 confirmed that thelaboratory scale process of Example 1 could be scaled up successfully.As shown in Table 3, Example 2 shows greater incorporation of sebacicacid compared to either Example 1 or Example 3, which is consistent withthe difference in charge ratios shown in Table 1.

Examples 4-5

The purpose of Examples 4-5 was to make the aliphatic-aromaticcopolyester PBT-co-adipate derived from PET in accordance to theinvention. The overall quantity of individual materials and the reactionscale used in the laboratory and pilot scale for Examples 1-3 are shownin Table 4.

TABLE 4 Amount of raw materials, reaction scale, and reaction conditionfor Examples 4-5. Scale of Catalyst EI EI Poly Poly Ex. Reaction PET:BDOADA:BDO Ti Temp. Time Temp. Time No. (g) (mol/mol) (mol/mol) (ppm) (°C.) (min) (° C.) (min) 4 143 0.39 0.39 100 220 33 230 65 5 27300 0.390.39 100 225 150 230 180

Techniques and Procedures Examples 4-5 Example 4

(PBT-co-adipate) (Example 4) was prepared in lab-scale from recycle PET,adipic acid (ADA) and 1,4-butanediol (BDO). 48 g of recycle PET, 36.5 gof ADA and 58 g of BDO were introduced into a three neck round bottomflask. The reactor was placed in an oil bath the temperature of whichwas adjusted to 170° C. 100 ppm of TPT was added to the reaction mixtureand the ester interchange temperature was increased to 220° C. with arate of 2° C./min while stirring at 260 rpm under nitrogen. Thetemperature of the reaction mixture was increased to 250° C. to melt theresidual PET flakes completely. The reactor temperature was thendecreased to 230° C. and the polymerization stage was initiated with thevacuum adjusted to below 1 Torr for 1 hour. At the end of thepolymerization stage, the vacuum was stopped. 0.05 wt. % phosphoric acidand 0.25 wt. % CESA (the multi-functional epoxy-based chain-extendermade from styrene-acrylic oligomer) were added to the melt and themixture was agitated for 30 minutes under nitrogen at atmosphericpressure.

Example 5

PBT-co-Adipate, Example 5 was prepared in a pilot plant scale-upfacility, which is described under the section, Example 3. 9.18 kg ofrecycle PET, 6.98 kg of adipic acid and 11.07 kg of 1,4-butanediol werecharged to the helicone reactor temperature of which was adjusted to170° C. 10.6 mL of TPT was added to the reaction mixture and the esterinterchange temperature was increased to 225° C. under nitrogen. Theagitator speed was set at 67% of maximum. The butanediol was refluxedinto the reactor for 2 hours. It should be noted that the design of theoverhead condenser system did not allow a complete reflux of thebutanediol. As a result, about 5 to 10 lbs (2.3 to 4.5 kg) of butanediolevolved in the initial stages could not be refluxed. The butanediolevolved after that could be completely refluxed into the reactor.

The temperature of the reaction mixture was increased to 250° C. to meltthe residual PET flakes completely. The speed of the agitator was set to60% of max and the target amps of the motor were 3.5 amps. The reactortemperature was then decreased to 230° C. and the polymerization stagewas initiated with the vacuum adjusted to below 1 Torr for 180 minutes.The reaction was carried out until the polymer mass reached its 2 andhalf build. Then, 13.61 g of phosphoric acid and 68.00 g of CESA wereadded to the melt and the mixture is agitated for 30 minutes undernitrogen at atmospheric pressure. The products were then allowed to dryand ground into pellets.

Results Examples 4-5

The results obtained for Examples 4 and 5 are shown in Table 5, Table 6,and FIG. 1. More particularly, Table 5 provides T_(g), T_(m), molecularweight, and I. V. Table 5 also shows MVR and MFR for Example 5. MVR andMFR on pellets (dried for 2 hours at 80° C. prior to measurement) weremeasured according to ISO 1133 at 190° C. and 2.16 kg. The compositionof the polymers obtained by ¹H NMR analysis is displayed in Table 6.FIG. 1 shows the apparent melt viscosity change of materials in Example4 versus various apparent shear rates in comparison with those of acommercial PBT-co-adipate copolymer. Diffuse reflectance was acquired ona Gretag Macbeth Color-Eye 7000A with D65 illumination, 10° observer,CIE L*, a*, b*, specular included, UV included, large lens position,large aperture. Table 6 shows the L*, a*, b* values of example 4 and 5.

TABLE 5 Thermal, molecular weight and I.V. analysis results for Examples4-5. MVR MFR Ex. Tg T_(m) (mL · 10 (mL · 10 No. (° C.) (° C.) M_(n)M_(w) PDI I.V. min⁻¹) min⁻¹) 4 −27 111 28200 134000 4.7 0.955 NA NA 5−27 107 30700 114900 3.70 1.134 10.81 10.27

TABLE 6 Composition analysis results obtained from H¹ NMR for Examples4-5. Isophthalic Terephthalic Adipic EG Ex. Groups Groups Groups BDOGroups No. Mole % Mole % Mole % Mole % Mole % 4 0.6 26.3 24.0 47.6 1.5 50.6 26.4 24.1 47.0 1.9

TABLE 7 Diffuse reflectance analysis of example 4-5. Ex. No. L* a* b* 478.892 −2.467 3.866 5 60.932 −1.801 9.502

FIG. 1 shows the apparent melt viscosity change of Example 5 versusvarious apparent shear rates in comparison with those of a commercialPBT-co-adipate copolymer.

Discussion Examples 4-5

The results of Examples 4 and 5 show that materials of Example 4 havethe low apparent shear rate viscosity at 170 and 190° C. due to its lowmelting temperature and molecular weight. However, the molecular weightof Example 5 is almost similar to the molecular weight of the commercialPBT-co-adipate. The melting temperature of Example 5 is 10° C. lowercompared to the commercial PBT-co-adipate (Commercial PBT-co-adipate,T_(m)=117° C., PBT-co-adipate prepared from PET, T_(m)=107° C. andPBT-co-sebacate prepared from PET, T_(m)=103° C.). Therefore, thePBT-co-adipate prepared from the PET process provides advantage for blowmolding at lower temperature. Since the molecular weights arecomparable, here the flow difference is mainly ascribed to the T_(m) ofthe polymers.

FIG. 1 shows the plot of the apparent shear viscosity of commercialPBT-co-adipate, Example 4, and Example 5, versus apparent shear rate.The high apparent shear viscosity at lower apparent shear rate isdesirable for blow molding processes. The apparent shear viscositydepends on the melting temperature and molecular weight of the targetedpolymers. The commercial PBT-co-adipate has the highest apparentviscosity at 170 and 190° C. because its melting temperature is 117° C.and molecular weight is 30400. Example 5, a pilot plant scale run,confirms that the laboratory scale process of Example 4 can besuccessfully scaled up.

Comparative Examples A-S

The purpose of these examples was to compare the effect of variousparameters on the process described in Example 4.

Techniques and Procedures Comparative Examples A-C

Copolyesters were prepared as described in Comparative Examples A-C toinvestigate the effect of the polymerization temperature on the finalcolor of PBT-co-adipate copolymer from recycle PET. The process ofExample 4 was repeated, except that the additives used and processconditions differed as described below.

The copolyester of Comparative Example A was prepared from 48 g ofrecycle PET, 36.5 g of adipic acid and 58 g of 1,4-butanediol. 100 ppmof TPT was added to the reaction mixture and the ester interchangetemperature was increased to 220° C. with a rate of 2° C./min whilestirring at 260 rpm under nitrogen. The temperature of the reactionmixture was increased to 250° C. and the polymerization stage wasinitiated with the vacuum adjusted to below 1 Torr for 30 minutes. Theresulting copolymer displayed red color. The result of the diffusereflectance analysis is given in Table 9.

In comparative Example B, the temperature of the reaction mixture wasincreased to 250° C. and then decreased to 220° C. The polymerizationstage was initiated with the vacuum adjusted to below 1 Torr for 1 hour.The resulting copolymer displayed slightly pink color.

The polymerization temperature of the comparative Example C was kept at200° C. under the vacuum adjusted to below 1 Torr for 170 minutes. Thefinal product showed white color.

Techniques and Procedures Comparative Examples D-F

The purpose of comparative examples D-F was to understand the effect ofaddition of a phenolic antioxidant in the composition containing thecopolyester. Comparative Examples D-F was prepared using the sameformulation reported above for Examples A to C with slight changes. Incomparative Examples D-E, 0.1 wt. % hindered phenolic antioxidantIRGANOX® 1330 was added to the formulations.

The polymerization temperature of Comparative Example D was kept at 250°C. under the vacuum adjusted to below 1 Torr for 30 minutes. Theresulting polymer was pink color.

The polymerization of Comparative Example E was carried out at 230° C.under the vacuum adjusted to below 1 Torr for 60 minutes. The resultingpolymer was white color.

In comparative Example F, 0.1 wt. % hindered phenolic antioxidantIRGANOX® 1010 was added to the same comonomer mixture. Thepolymerization temperature was 230° C. and a constant vacuum adjusted to1 Torr was applied for 60 minutes. The polymer displayed red color.

Techniques and Procedures Comparative Examples G-I

In these Comparative Examples, tetrabutyl orthotitanate (TOT) was usedto understand the effect if any, of the catalyst on the final color ofthe copolymer resin. Comparative Examples G-I was implemented using thesame formulation except for polymerization catalyst.

Comparative Example G was prepared in the presence of 100 ppm of TOT. Apolymerization build was not observed.

Comparative Examples H-I were prepared in the presence of TOT-TPTcatalyst mixture at polymerization temperature of 250 and 230° C.respectively. Dark brown and pale brown colors were observed.

Techniques and Procedures Comparative Examples J-S

The purpose of Comparative Examples J-S was to understand the effect ofphosphate additives and/or glycidyl copolymer additives in thecopolyesters. Comparative Examples J-S were prepared using the samepolymerization condition described above.

In comparative Examples J-O, 0.05 wt. % of MZP, TNPP, SDP, SAPP,triisododecyl phosphate, and triphenylphosphite were respectively addedto the melt and the respective mixture was agitated for 30 minutes undernitrogen at atmospheric pressure.

Comparative Examples P-Q were prepared with the addition of 0.01 wt. %phosphoric acid and 0.1 wt. % phosphoric acid to the melt. The viscosityof the resulting mixture dropped for both Examples.

Comparative Example R was prepared with the addition of 0.25 wt. % ofCESA. A viscosity increase was observed, but the color of the polymerremained red. In Comparative Example S, 0.25 wt. % CESA and 0.05 wt. %phosphoric acid were added to the melt and the mixture is agitated for30 minutes under nitrogen at atmospheric pressure. The color of thepolymer changed into pale yellow.

Results Comparative Examples A-S

Table 8 summarizes the additive, polymerization time, thermal, molecularweight, polydispersity index, intrinsic viscosity and color data of theComparative Examples A-S.

TABLE 8 Additive, thermal, molecular weight, and results of comparativeexamples. Ex. Poly Poly T_(g) T_(m) No. Add. PI Temp. (° C.) Cat. Time(° C.) (° C.) M_(n) M_(w) I.V. Color 4 CESA + 4.7   230 C. TPT 65 −27111 28200 134000 0.955 White HP A** None 4.6 250 TPT 27 −24 116 27500125000 0.991 Red B* None 6.2 220 TPT 85 −29 111 28000 173000 0.976 PinkC* None 5.5 200 TPT 120 −25 112 31000 170000 1.095 White D IR 1330 7.6250 TPT 28 −24 115 26000 198000 0.807 Pink E IR 1330 6.1 230 TPT 58 −24114 29500 179000 1.142 White F IR 1010 7.1 230 TPT 57 −24 114 29500210000 1.179 Red G None 250 TOT H None 3.4 250 TOT + 32 −23 114 2820096000 0.952 Dark TPT Brown I None 3.2 230 TOT + 66 −25 113 30100 975001.017 Pale TPT Brown J MZP 3.5 250 TPT 26 −25 117 23500 81500 0.960Brown K TNPP 3.3 250 TPT 28 −24 114 27500 91000 0.963 Brown L SDP 2.6250 TPT 27 −27 118 16300 42000 0.550 Pink M SAPP 3.7 250 TPT 28 −28 11522000 82000 0.735 Pink N TIDPe 3.3 250 TPT 25 −24 116 28000 92000 0.932Brown O TPP 2.6 250 TPT 30 −27 117 12500 31500 0.376 Pink P Low HP 2.8250 TPT 31 −25 118 20500 58000 0.718 Pink Q High HP 3.2 250 TPT 27 −32117 9000 28500 0.232 Yellow R Cesa 5.1 250 TPT 27 −17 108 17000 860001.253 Red S Cesa + 3.0 250 TPT 32 −27 118 17000 51000 0.568 Pale HPYellow *Polydispersity Index **Composition disclosed U.S. Pat. No.5,446,079 and U.S. Publication No. 20080081898

TABLE 9 Diffuse reflectance analysis of example A. Ex. No. L* a* b* A61.97 12.21 13.64

Discussion Comparative Examples A-S

The results of Comparative Examples A-S show that a good balance ofproperties such as white color, high molecular weight, and apolydispersity index of less than 6, and an acceptable reaction time forthe preparation of copolyesters can be achieved only when appropriatecombination of additives and temperature are chosen for the reactions.

When copolyesters are not made with an additive combination containing aphosphate group and an addition copolymer based on a glycidyl monomer,and when the process is carried out at a temperature that is 250° C. ormore, the copolyesters that are produced do not exhibit desired balanceof properties. For instance, the copolyesters of Comparative Examples A,B, D, F, H, I, J, K, L, M, N, O, P, Q, R, S were not white. Thecopolyesters obtained in Comparative Examples C and E were acceptablywhite, but had a polydispersity index value greater than 5, which wasundesired. The copolyester of invention, Example 4, where a combinationof CESA and phosphoric acid is used at 230° C., exhibited a good balanceof properties including color and polydispersity as shown in Table 7.The copolyesters of Comparative Examples A, D, H, J, K, L, M, N, O, P,Q, R and S, which were polymerized at 250° C. were all colored, thoughthe copolyester of Comparative Example S, based on a combination ofphosphate and addition copolymer, CESA provided the least intenselycolored sample (pale yellow color). It is important to note that at 250°C., as per examples, S, R, and Q, a combination of CESA and phosphoricacid is more effective than the individual additives in reducing theintensity of coloration.

Examples 6-7

The purpose of Examples 6-7 was to prepare the copolyesterPPT-co-sebacate derived from PET

The overall quantity of individual materials and the reaction scale usedin the laboratory and pilot scale for Examples 1-3 are shown in Table10.

TABLE 10 Amount of raw materials, reaction scale and reaction conditionfor Examples 6-7. Scale of Catalyst EI EI Poly Poly Ex. Reaction PET:PDOSBA:PDO Ti Temp. Time Temp. Time No. (g) (mol/mol) (mol/mol) (ppm) (°C.) (min) (° C.) (min) 6 143 0.39 0.39 100 220 50 230 66 7 9100 0.170.17 100 185 60 260 120

Techniques and Procedures Examples 6-7 Example 6

PPT-co-sebacate was prepared from recycle PET, sebacic acid, and1,3-propanediol. Then, 48 g of recycle PET, 50.4 g of sebacic acid and54 g of 1,3-propanediol were introduced into a three neck round bottomflask. The reactor was placed in an oil bath the temperature of whichwas adjusted to 170° C. TPT was added to the reaction mixture and theester interchange temperature was increased to 220° C. with a rate of 2°C./min while stirring at 260 rpm under nitrogen. The reaction mixturewas increased to 250° C. to melt any residual PET flakes. Polymerizationstage was conducted at 230° C. with the vacuum adjusted to below oneTorr for 1 hour.

Example 7

In Example 7, PPT-co-sebacate was prepared in a larger scale incomparison to the Example 6. The procedure followed for the preparationwas similar to the procedure used in Example 6 and the molar ratio ofPET:PDO and SBA:PDO was used as indicated in Table 10.

Results Examples 6-7

Table 11 shows the T_(g), T_(m) obtained by DSC, molecular weight, meltvolume rate (MVR), melt flow rate (MFR) and I. V. for the Examples 6-7.The compositions of the Examples 6-7 obtained through ¹H NMR analysisare shown in Table 12.

TABLE 11 Thermal, molecular weight, and I.V. analysis results MVR MFREx. T_(g) T_(m) (mL · 10 (mL · 10 No (° C.) (° C.) M_(n) M_(w) PDI I.V.min⁻¹) min⁻¹) 6 −32 107 30103 97570 3.20 1.067 NA NA 7 −23 120 45000134000 3.00 1.249 10.04 10.71 NA—‘not available’.

TABLE 12 Composition analysis results of PPT-co-sebacate. IsophthalicTerephthalic Sebacic EG Ex. Groups Groups Groups PDO Groups No. Mole %Mole % Mole % Mole % Mole % 6 0.6 26.3 24.0 47.6 1.5 7 0.7 24.6 28.345.9 0.5

Discussion Examples 6-7

The results in Tables 11 and 12 show that a copolyester, PPT-co-sebacatederived from PET was successfully prepared in accordance with theinvention. The results show that the process that was used to make thecopolyester enabled a high molecular weight of copolyester. The resultsalso show that residues of the poly(ethylene terephthalate) that wasused to make the copolyester were incorporated into the copolyester.Also, as seen in Tables 11 and 12, PPT-co-sebacate copolyester ofdifferent T_(g)s and T_(m)s can be obtained by varying the chargeratios, PET:PDO and SBA:PDO as shown in Table 10.

Examples 8-9

The purpose of Examples 8-9 was to prepare copolyester moldingcompositions containing a nucleating agent and a thermal stabilizer.

Techniques and Procedures Examples 8-9 Example 8

Example 8 was prepared by dry mixing PBT-co-adipate copolymer derivedfrom PET from Example 5 99.8%, ultra talc 0.1%, and IRGANOX® 1330 0.1%in a tumble dryer and then extruding the mix on a 30 mm twin screwextruder (with a maximum capacity of 75 lbs/hr) having 2 feeders and avacuum vented mixing screw. The feed temperature was 194° F. (90° C.).The extrusion temperature was usually maintained between 248 and 367° F.(120 and 186° C.). The screw speed was 300 rpm. The extrudate was cooledthrough a water bath prior to pelletizing. Test parts were injectionmolded on a van Dorn molding machine. The pellets were dried for 1 hourat 115° F. (46° C.) in a forced air-circulating oven prior to injectionmolding. The zone temperature was set to 360° F. (183° C.). The moldtemperature was 70° F. (21° C.). All standard parts were 0.125 inches(3.12 mm) thick.

Example 9

Example 9 was prepared by dry mixing PBT-co-sebacate resin derived fromPET 99.8%, ultra talc 0.1%, and IRGANOX® 1330 0.1% in a tumble dryer andthen extruding the mix on a 30 mm twin screw extruder (with a maximumcapacity of 75 lbs/hr) having 2 feeders and a vacuum vented mixingscrew. The feed temperature was 194° F. (90° C.). The extrusiontemperature was usually maintained between 248 and 367° F. (120 and 186°C.). The screw speed was 300 rpm. The extrudate was cooled through awater bath prior to pelletizing. Test parts were injection molded on avan Dorn molding machine. The pellets were dried for 1 hour at 115° F.(46° C.) in a forced air-circulating oven prior to injection molding.The zone temperature was set to 360° F. (182° C.). The mold temperaturewas 70° F. (21° C.). All standard parts were 0.125 inches (3.12 mm)thick.

Testing Procedure for Molding Compositions

Injection molded parts were tested in accordance with ASTM methods.Notched Izod testing is done on three×½×⅛ inch (76.2×12.7×3.2 mm) barsusing ASTM method D256. Bars were notched prior to oven aging; sampleswere tested at room temperature. Unnotched Izod testing is done on 3×½×⅛inch (76.2×12.7×3.2 mm) bars using ASTM D 4812. The tensile propertiesof low-modulus plastic are determined based on ASTM D638 using 7×⅛ in.(177.8×3.3 mm) injection molded dumbbell-shaped bars. The test employs acrosshead speed of 2 inches per minute and runs until the sample breaksor the crosshead reaches its extension limit. Flexural properties weremeasured using ASTM 790 or ISO 178 method. Heat deflection temperaturewas tested on five bars having the dimensions 5×0.5×0.125 inches(127×12.7×3.2 mm) using ASTM method D648. The black specs were measuredby counting the black specs present visually on the surface of a Dynatupdisc.

A synopsis of the tests and test methods is given in Table 13.

TABLE 13 Test Methods and Descriptions Test Standard Default SpecimenType Units ASTM Flexural Test ASTM D790 Bar - 127 × 12.7 × 3.2 mm MPaASTM HDT Test ASTM D648 Bar - 127 × 12.7 × 3.2 mm ° C. ASTM For Lowmodulus ASTM D638 ASTM Type I Tensile bar MPa Plastics Tensile Test ASTMIzod at Room Notched ASTM D256 Bar - 63.5 × 12.7 × 3.2 mm J/mTemperature ASTM Izod at Room Unnotched ASTM D4812 Bar - 63.5 × 12.7 ×3.2 mm J/m Temperature

Results Examples 8-9

The physical testing results of the molding compositions, Examples 8 and9 are shown in Table 14.

TABLE 14 Physical testing results of Examples 8-9 PBT-co-adipate,PBT-co-sebacate, Commercial (Example 8) (Example 9) Tests UnitsPBT-co-adipate derived from PET derived from PET HDT at Stress of 0.455MPa ° C. 39.50 40.20 37.40 HDT at Stress of 1.82 MPa ° C. 35.50 36.7027.30 Flexural Modulus MPa 107.00 86.80 48.60 Flexural Modulus at 5%Strain MPa 5.00 4.17 2.89 Flexural Stress at Yield MPa 6.94 6.03 2.77Flexural Stress at Break MPa 0.42 IZOD Impact Notch, 23 C. J/m 220.00198.00 136.00 IZOD Impact Unnotched 23° C. J/m 240.00 190.00 120.00Modulus of Elasticity-Avg MPa 97.00 79.00 48.00 Stress at 5% Strain-AvgMPa 1.10 0.90 0.60 Stress at 10% Strain-Avg MPa 6.00 5.00 3.50 Stress at50% Strain-Avg MPa 6.80 5.80 4.10 Stress at Break-Avg MPa 15.00Elongation at Break-Avg % 349.00 Nominal Strain at Break-Avg % 1527.50

Discussion Examples 8-9

As seen in Table 14, both the copolyesters, PBT-co-adipate derived fromPET pellets and PBT-co-sebacate derived from PET pellets, havemechanical properties that are different from those of a commercialcopolyester sample of PBT-co-adipate, though the thermal properties (HDTvalues) appear to be similar. Between PBT-co-adipate derived from PETpellets and PBT-co-sebacate derived from PET pellets, the former hasproperties closer to those of the commercial samples of PBT-co-adipate.The flexural modulus, Izod impact, and modulus of elasticity ofPBT-co-adipate and PBT-co-sebacate are lower compared to commercialPBT-co-adipate resin. Especially, PBT-co-sebacate prepared from PETshows very low crystallinity resulting in high flexibility. In addition,molded parts of PBT-co-adipate prepared from PET pellets andPBT-co-sebacate prepared from PET pellets did not break at maximumelongation. The low crystalline nature, higher flexibility and higherresistance to maximum elongation of PBT-co-adipate prepared from PET andPBT-co-sebacate prepared from PET may provide several advantages in blowextrusion processes and final film properties, such as easy stretchingcondition, energy saving, high transparency and thinner films.

Examples 10-11

The purpose of Examples 10 and 11 was to prepare combinations ofPBT-co-adipate from PET pellets and PBT-co-sebacate from PETrespectively with starch.

Techniques and Procedures Examples 10-11 Example 10

Example 10 was prepared by dry mixing corn starch 30.0%, PBT-co-adipatecopolymer 69.9%, and IRGANOX® 1330 0.1% in a tumble dryer and thenextruding the mix on a 30 mm twin screw extruder (with a maximumcapacity of 75 lbs/hr) having 2 feeders and a vacuum vented mixingscrew. The feed temperature was 320° F. (160° C.). The extrusiontemperature was usually maintained between 248 and 320° F. (120 and 160°C.). The screw speed was 300 rpm. The extrudate was cooled through awater bath prior to pelletizing. Test parts were injection molded on avan Dorn molding machine. The pellets were dried for 1 hour at 115° F.(46° C.) in a forced air-circulating oven prior to injection molding.The zone temperature was set to 360° F. (183° C.). The mold temperaturewas 70° F. (21° C.). All standard parts were 0.125 inches (3.12 mm)thick.

Example 11

The purpose of Example 11 was to prepare a combination ofPBT-co-sebacate from PET with starch. Example 11 was prepared by drymixing corn starch (30.0 wt. %), PBT-co-sebacate (69.9 wt. %), andIRGANOX® 1330 (0.1 wt. %) in a tumble dryer and then extruding the mixon a 30 mm twin screw extruder (with a maximum capacity of 75 lbs/hr)having 2 feeders and a vacuum vented mixing screw using the samecompounding condition mentioned in the Examples 10.

Examples 12-13

The purpose of Examples 12 and 13 was to prepare the combinations ofPBT-co-adipate derived from PET pellets and PBT-co-sebacate derived fromPET respectively with PLA.

Techniques and Procedures Examples 12-13 Example 12

A copolyester combination was prepared by dry mixing PLA (45. wt. %),PBT-co-adipate copolymer derived from PET (54.9 wt. %), and IRGANOX®1330 (0.1 wt. %) in a tumble dryer and then extruding the mix on a 30 mmtwin screw extruder (with a maximum capacity of 75 lbs/hr) having 2feeders and a vacuum vented mixing screw. The feed temperature was 320°F. (160° C.). The extrusion temperature was usually maintained between320 and 329° F. The screw speed was 300 rpm. The extrudate was cooledthrough a water bath prior to pelletizing. Test parts were injectionmolded on a van Dorn molding machine. The pellets were dried for 1 hourat 115° F. (46° C.) in a forced air-circulating oven prior to injectionmolding. The zone temperature was set to 360° F. (183° C.). The moldtemperature was 70° F. (21° C.). All standard parts were 0.125 inches(3.12 mm) thick.

Example 13

Example 13 was prepared by dry mixing PLA (45.0 wt. %, PBT-co-sebacatecopolymer (54.9 wt. %, and IRGANOX® 1330 (0.1 wt. %) in a tumble dryerand then extruding the mix on a 30 mm twin screw extruder (with amaximum capacity of 75 lbs/hr) having 2 feeders and a vacuum ventedmixing screw using the same compounding condition stated in Examples 12.

Results Examples 12-13

The results of physical testing of the PLA combinations, Examples 12 and13 are given in the Table 15.

TABLE 15 Physical testing results of Example 12 and Example 13. PLA +PLA + PBT-co Adipate PLA + PBT-co-Sebacate Commercial PBT- derived fromPET derived from PET Tests Units co-Adipate** (Example 12) (Example 13)HDT at Stress of 1.82 MPa ° C. 45.40 47.30 47.70 Flexural Modulus MPa779.00 1270.00 1270.00 Flexural Stress at Yield MPa 24.10 34.20 30.40Flexural Stress at 5% Strain MPa 22.00 34.10 29.50 IZOD Impact Notch, 23C. J/m 927.00 1230.00 1010.00 IZOD Impact Unnotched 23° C. J/m 968.001380.00 967.00 Modulus of Elasticity-Avg MPa 778.00 1280.00 1254.00Stress at 5% Strain-Avg MPa 5.90 9.30 8.90 Stress at 10% Strain-Avg MPa16.00 21.00 18.80 Stress at 50% Strain-Avg MPa 16.00 15.80 15.90 Stressat Break-Avg MPa 17.30 9.40 17.10 Elongation at Break-Avg % 356.30229.20 315.00 Nominal Strain at Break-Avg % 1293.00 428.00 666.70**Combination with commercial copolyester prepared in accordance to theprocedure described above in Example 13.

Discussion Examples 10-13

As seen in Table 13, the combinations of PLA with the copolyesters,either PBT-co-adipate derived from PET or PBT-co-sebacate derived fromPET, have comparable or superior mechanical properties when comparedwith a commercial sample of PLA-PBT-co-adipate combination. Themechanical properties, particularly, flexural modulus, flexural stress,Izod impact values, modulus of elasticity and stress and 5-10% strainvalues of a combination of PLA with PBT-co-adipate derived from PET aresuperior to those of both the PLA combinations of commercial sample ofPBT-co-adipate derived from PET and PBT-co-sebacate derived from PET.The Examples 12 and 13 are non-limiting examples, and for a personskilled in the art, numerous combination compositions would therefore bepossible to tune the properties of these combinations to the extentdesired.

All cited patents, patent applications, and other references areincorporated herein by reference in their entirety.

Although the present invention has been described in detail withreference to certain preferred versions thereof, other variations arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the versions contained therein.

What is claimed is:
 1. A biodegradable composition comprising acombination of: (i) from more than 10 to 59.99 wt. %, based on the totalweight of the composition, of an aliphatic aromatic copolyester having anumber average molecular weight of at least 20,000 Daltons and apolydispersity index from 2 to less than 6, wherein the aliphaticaromatic copolyester comprises the following groups incorporated intothe copolyester via glycolysis and polymerization: (a) a first dihydricalcohol group derived from a first dihydric alcohol selected from thegroup consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propyleneglycol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, tetramethylcyclobutanediol, isosorbide, cyclohexanedimethanol, hexylene glycol,bio-derived diols, and a combination thereof, (b) an aromaticdicarboxylic acid group derived from a reaction of (bi) the firstdihydric alcohol, (bii) an aromatic polyester selected from the groupconsisting of poly(ethylene terephthalate), poly(butyleneterephthalate), polytrimethylene terephthalate, and a combinationthereof, and (biii) an aliphatic dicarboxylic acid having the generalformula (CH₂)_(m)(COOH)₂ where m is an integer from 2 to 10, (c) analiphatic dicarboxylic acid group derived from the aliphaticdicarboxylic acid having the general formula (CH₂)_(m)(COOH)₂ where m isan integer from 2 to 10, (d) a second dihydric alcohol group derivedfrom the aromatic polyester and incorporated into the aliphatic aromaticcopolyester when the aromatic polyester reacts with the first dihydricalcohol and the aliphatic dicarboxylic acid, wherein the second dihydricalcohol group is the residue of ethylene glycol, 1,2-propylene glycol,1,3-propylene glycol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol,tetramethyl cyclobutanediol, isosorbide, a cyclohexanedimethanol, ahexylene glycol, a bio-derived diol, or a combination thereof, (e) theresidue of from 0 to 0.10 wt. %, based on the aliphatic-aromaticcopolyester, of a phosphate compound, and (f) the residue of from 0 to1.50 wt. %, based on the aliphatic-aromatic copolyester, of an additioncopolymer comprising the residue of a glycidyl monomer; (ii) from morethan 40 to less than 89.99 wt. %, based on the total weight of thecomposition, of an aliphatic polyester, aliphatic polycarbonate, starch,aromatic polyester, cycloaliphatic polyester, polyesteramide, oraromatic polycarbonate; and (iii) from 0.01 to 5.00 wt. %, based on thetotal weight of the composition, of a nucleating agent, an antioxidant,a UV stabilizer, a plasticizer, an epoxy compound, a melt strengthadditive, or a combination thereof; wherein the wt. % of (i), (ii), and(iii) totals 100 wt. %; and wherein a bar having a thickness of 3.2 mmmolded from the composition has a notched Izod impact strength of atleast 920 μm determined in accordance with ASTM D256 at 23° C., and aflexural modulus of at least 750 MPa determined in accordance with ASTMD790.
 2. The composition of claim 1, wherein the first dihydric alcoholgroup is present in an amount from 80 to 99.6 mole % of the totaldihydric alcohol content and the second dihydric alcohol group ispresent in an amount from 0.4 mole % to 20.0 mole % of the totaldihydric alcohol content.
 3. The composition of claim 1, wherein thearomatic dicarboxylic group and the aliphatic dicarboxylic group have anaromatic dicarboxylic group:aliphatic dicarboxylic mole ratio from 0.6:1to 6:1.
 4. The composition of claim 1, wherein the aromatic dicarboxylicacid group contains from 0.2 to 3.0 mole % of isophthalic acid groupsand from 47 to 49.8 mole % terephthalic acid groups, each based on thetotal moles of dicarboxylic acid groups in the aliphatic aromaticcopolyester.
 5. The composition of claim 1, wherein the additioncopolymer comprises the residue of glycidyl acrylate, glycidylmethacrylate, or a combination thereof; and the residues of methylmethacrylate, methyl acrylate, styrene, alpha-methyl styrene, butylmethacrylate, butyl acrylate, or a combination thereof.
 6. Thecomposition of claim 1, wherein the aliphatic polyester is poly(lacticacid), a (hydroxyalkanoate), poly(butylene succinate), poly(butyleneadipate), poly(butylene succinate adipate), poly(caprolactone), or acombination thereof.
 7. The composition of claim 1, wherein the firstdihydric alcohol is 1,4-butanediol, 1,3-propanediol, ethylene glycol, ora combination thereof, and the second dihydric alcohol group is theresidue of ethylene glycol, 1,3-propanediol, 1,4-butanediol, or acombination thereof.
 8. The composition of claim 1, wherein thealiphatic dicarboxylic acid is decanedioic acid, adipic acid, sebacicacid, or a combination thereof.
 9. The composition of claim 1, whereinthe aromatic polyester is poly(butylene terephthalate) and thealiphatic-aromatic copolyester comprises a butane diol group, titanium,tin, an epoxy, or a combination thereof.
 10. The composition of claim 1,wherein the aromatic polyester is poly(trimethylene terephthalate) andthe aliphatic-aromatic copolyester comprises a propane diol group,titanium, tin, or a combination thereof.
 11. The composition of claim 1,wherein the aromatic polyester is a poly(ethylene terephthalate)homopolymer, (ethylene terephthalate) copolymer, or a combinationthereof, and the aliphatic-aromatic copolyester comprises an ethyleneglycol group, diethylene glycol group, isophthalic acid group,antimony-containing compound, germanium-containing compound,titanium-containing compound, cobalt-containing compound, tin-containingcompounds, aluminum, aluminum salt, 1,3-cyclohexanedimethanol isomer,1,4-cyclohexanedimethanol isomer, alkaline salt, alkaline earth metalsalt, phosphorous-containing compound or anion, sulfur-containingcompound or anion, naphthalene dicarboxylic acid group, 1,3-propanediolgroup, or a combination thereof.
 12. The composition of claim 11,wherein the aliphatic-aromatic copolyester comprises an ethylene glycolgroup and a diethylene glycol group.
 13. The composition of claim 12,wherein the aliphatic-aromatic copolyester further comprises isophthalicacid groups.
 14. The composition of claim 13, wherein thealiphatic-aromatic copolyester further comprises a cis isomer of1,3-cyclohexanedimethanol group, cis isomer of 1,4-cyclohexanedimethanolgroup, trans isomer of 1,3-cyclohexanedimethanol group, trans isomer of1,4-cyclohexanedimethanol group, or a combination thereof.
 15. Thecomposition of claim 11, wherein the aliphatic-aromatic copolyestercomprises an ethylene glycol group, diethylene glycol group, and acobalt-containing compound.
 16. The composition of claim 15, wherein theat least one residue derived from the poly(ethylene terephthalate)homopolymer, (ethylene terephthalate) copolymer, or a combinationthereof further comprises isophthalic acid groups.
 17. The compositionof claim 1, wherein the aliphatic-aromatic copolyester has a Tg from−35° C. to 0° C.
 18. The composition of claim 1, wherein thealiphatic-aromatic copolyester has a Tm from 90° C. to 160° C.
 19. Anarticle extruded, calendared, extrusion molded, blow molded or injectionmolded from the composition of claim
 1. 20. The article of claim 19,wherein the article is a film.
 21. The film of claim 20, wherein thefilm is formed by extrusion molding or calendaring the composition ofclaim
 1. 22. The film of claim 21, wherein the film has a modulus ofelasticity of at least 520 N/mm² as determined in accordance with as ISO527, a tensile strength of at least 27 N/mm² as determined in accordancewith as per ISO 527, a tear strength of at least 38 J/mm as determinedin accordance with as DIN 53373.